1. Field of the Invention
The present invention relates to an inverter device including a plurality of switching elements that convert electric power between DC power and AC power, a base plate that includes an element placing surface on which these plurality of switching elements are placed, heat dissipating fins that are provided on the side of the base plate opposite to the element placing surface, AC terminals through which AC power is input and output to and from a rotary electric machine as a driving power source of a vehicle and which are electrically connected to the switching elements, and a capacitor that smoothes DC power.
2. Description of the Related Art
In recent years, a hybrid vehicle or an electric vehicle, which includes a rotary electric machine as a driving power source, has come into the spotlight in terms of energy saving or the reduction of environmental burden. There are many cases where a DC power source such as a high-voltage battery is generally provided and the rotary electric machine is driven by AC power in the hybrid vehicle or the like. For this reason, the hybrid vehicle or the like is provided with an inverter device between the DC power source and the rotary electric machine.
A device disclosed in, for example, the following JP-A-2008-29094 has already been known as the above-mentioned inverter device. Hereinafter, names and reference numerals of corresponding members disclosed in JP-A-2008-29094 will be quoted in square brackets in the description of the section of the background art. As shown in FIGS. 2 and 3 of JP-A-2008-29094, this device includes a base plate [motor substrate 120 and cooling fins 12] on which a plurality of switching elements [MOS-FETs 111a to 111f] are provided, heat dissipating fins [cooling fins 12] that are provided on the side opposite to the surface of the base plate on which the switching elements are placed, a plurality of AC phase-terminals [AC terminals 71, 72, and 73] through which AC power is input and output to and from a rotary electric machine [motor generator 940], and capacitors [electrolytic capacitors 21, 22, and 23] that smooth DC power.
In JP-A-2008-29094, the inverter device and the rotary electric machine are disposed so as to be distant from each other in the width direction of a vehicle. Further, the disposition of the plurality of AC phase-terminals, the heat dissipating fins, and the capacitors when the inverter device is mounted on the vehicle is not clearly described in JP-A-2008-29094. However, referring to FIGS. 2, 5, and 7 of JP-A-2008-29094 together, it is understood that the plurality of AC phase-terminals are sequentially arrayed in the direction parallel to a rotating shaft of the rotary electric machine and the capacitors are disposed on the front side of the heat dissipating fins in a travel direction of the vehicle.
However, in this structure, an electrical connection structure between the rotary electric machine and the plurality of AC phase-terminals of the inverter device is apt to be increased in size and become complicated. Further, in relation to the travel direction of the vehicle, the cooling fins are hidden in the shade of the capacitors that occupies a relatively large range in the direction perpendicular to the base plate. For this reason, there is a possibility that it is not possible to efficiently cool both the capacitors and the switching elements. That is, when the performance for cooling the components (the switching elements, the capacitors, or the like) of the inverter device or the electrical connection between the inverter device and the rotary electric machine as a driving power source of the vehicle is considered, the disposition of the respective components of the inverter device disclosed in JP-A-2008-29094 is not necessarily optimized.